IN PHOTO: Cast Member Grant Gustin Attends A Panel For The CW Television Series 'The Flash.'
IN PHOTO: Cast member Grant Gustin attends a panel for The CW television series "The Flash" during the Television Critics Association Cable Summer Press Tour in Beverly Hills, California July 18, 2014. MARIO ANZUONI/Reuters

"The Flash" Season 1, Episode 4, titled "Going Rogue," airs Tuesday, Oct. 28, on The CW. Felicity Smoak (Emily Bett Rickards) from the network's other DC Comics-inspired series, "Arrow," is crossing over. And Central City's villain of the week is Captain Cold (Wentworth Miller).

Spoiler alert: This update contains more spoilers on The Flash (2014) Season 1. Read at your own risk if you have not seen the previous episodes.

The CW has released an elaborate synopsis, as seen on flashtvnews.com:

"The Flash (Grant Gustin) stops a robbery but the culprits get away after shooting a guard, and The Flash chooses to save the man instead of following the criminals. Joe (Jesse L. Martin) shows Barry a book of suspects and Barry identifies Leonard Snart (guest star Wentworth Miller, "Prison Break") as the leader of the group."

The Flash Season 1, Episode 4 synopsis continues: "While investigating the case, Barry gets a surprise visit from an old friend -Felicity Smoak..."

In "Arrow" Season 3, Episode 2 (aired Oct. 22), Felicity tells Ray Palmer that she is visiting a friend who has gotten out of coma. (Palmer is portrayed by Brandon Routh, character's alter-ego is Atom in DC Comics.)

Fans would recall that in the pilot episode of The Flash, Stephen Amell's Oliver Queen shows up to give Barry some words of encouragement. Spoiler reports say there will be at least one more crossover on both shows.

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"(Felicity Smoak) joins (Barry Allen) at S.T.A.R. Labs to help stop Snart after it's revealed that Snart his gotten his hands on a stolen "cold gun," which could kill The Flash. Dr. Wells (Tom Cavanagh) is furious when he finds out that Cisco (Carlos Valdes) built the cold gun without telling anyone and now it's missing. Meanwhile, Iris (Candice Patton) is getting the silent treatment from Joe because of her relationship with Eddie (Rick Cosnett). Finally, The Flash and Captain Cold have an epic confrontation. Glen Winter directed the episode written by Geoff Johns & Kai Yu Wu," concludes the episode synopsis.

Dr Wells is in the final act of The Flash in the first three episodes. If he continues the pattern, fans will find out more clues as to who could he really be, and which side he's on.

VIDEO: The Flash Season 1, Episode 4 Promo Video | The CW on YouTube

The Flash airs Tuesdays on The CW. Arrow, meanwhile, airs Wednesdays in the same network.

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